Ball milling-MnO₂ enables viable straw blanket production via lignin depolymerization

The efficient cleavage of lignin is critical for unlocking the mechanical potential of straw fibers. This study introduces an industrially scalable strategy that integrates mild lignin depolymerization using low-cost ball-milled MnO₂ with subsequent straw blanket production. At 35 °C, bm-MnO₂ optimized under 180  min of ball milling at 400  rpm with a ball-to-sample ratio of 22:1 achieved 91% lignin decomposition by cleaving β-O-4/β-1 linkages, reducing its molecular weight by 65.02% and yielding valuable aromatics. Such strong oxidizability is attributed to increased oxygen vacancies via ball-milling, generating more Mn³⁺ and O₂^-, where Mn³⁺ initiates the decomposition and O₂^- propagates it, as elucidated by density functional theory (DFT) calculations. The processed fibers were directly fabricated into functional straw blankets. Mechanical tests showed that the straw blankets exhibited optimal mechanical properties (tensile strength 18.6  MPa, elongation at break 11.5%), while meeting application requirements partial lignin depolymerization accelerated the biodegradation process. Techno-economic analysis reveals that every $1 invested in MnO₂ boosts the profit from blanket production by $476, a 44.78% increase in profit margin compared to untreated straw fabric while life cycle assessment shows a nearly 90% lower environmental impact versus commercial straw particleboard. Successfully applied in practice, this approach provides a sustainable pathway for converting waste straw into high-value products for agricultural and ecological uses.